Effects of local autonomy of global concurrency control in heterogeneous distributed database systems

A heterogeneous distributed database system (HDDBS) is a system which integrates preexisting database systems to support global applications accessing more than one database. The difficulties and general approaches of global concurrency control in HDDBSs are studied. In particular, the author discusses the difficulties of maintaining global serializability in HDDBSs. The need for new strategies is established, and counterexamples to existing algorithms are given. An assumption usually made in addressing multidatabase systems is that the element databases are autonomous. The meaning of autonomy and its effects on designing global concurrency control algorithms are addressed. It is the goal of this study to motivate other researchers to realize the need for new correctness criteria by which concurrency control algorithms can be validated